JPH0780986A - Gas barrier film - Google Patents

Abstract

PURPOSE:To obtain a film suppressing the lowering of gas barrier properties caused by the action of mechanical external force such as rubbing and having excellent gas barrier properties even at high temp. even if a coating layer is thin in addition to transparency. CONSTITUTION:At least one surface of a base material film layer composed of polyester is successively coated with a transparent inorg. layer constituted of silicon oxide and a barrier resin coating layer containing a barrier resin such as a vinylidene chloride copolymer or an ethylene/vinyl alcohol copolymer to obtain a gas barrier film. The thickness n1 is the inorg. layer is 0.01-0.5mum and the thickness n2 of the barrier resin coating layer is 0.05-15mum and the thickness ratio n2/n1 is 0.1-1500.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas barrier film which is transparent and has an excellent gas barrier property against water vapor, oxygen, etc. and which is suitable as a packaging film for foods, pharmaceuticals, precision electronic parts and the like.

[0002]

2. Description of the Related Art Packaging films used for foods, pharmaceuticals, precision electronic parts, etc. are required to have high transparency for the visibility and aesthetic appearance of the contents, and also due to moisture absorption and oxidation of the contents. A gas barrier property is required to prevent alteration and the like.

Therefore, in JP-A-55-59961, the surface of a base film such as a polyester film or a polypropylene film is coated with a polymer having an excellent gas barrier property such as vinylidene chloride or an ethylene-vinyl alcohol copolymer. Alternatively, a laminated film is disclosed. However, although a film obtained by laminating a gas barrier polymer is excellent in transparency, the gas barrier property against water vapor, oxygen, etc. is still insufficient. In particular,
At high temperatures, gas barrier properties against water vapor, oxygen, etc. are significantly reduced.

On the other hand, a composite film in which an inorganic thin film is formed on a base material film, for example, a film obtained by vapor deposition of silicon oxide (Japanese Patent Publication No. 53-12953, JP-A-4-17).
3137), a film obtained by vacuum-depositing magnesium fluoride or the like (JP-A-1-297237), and the like. However, in such a composite film, when the thickness of the inorganic layer is increased in order to obtain a high gas barrier property against water vapor, oxygen, etc., the transparency is lowered, the flexibility is lowered, and cracks or peeling are caused. Occurs. On the other hand, if the film thickness is reduced to ensure transparency, sufficient gas barrier properties cannot be obtained. Further, the above-mentioned Japanese Patent Laid-Open No. 4-17
Japanese Patent No. 3137 describes a composite film obtained by vapor-depositing silicon oxide on polyvinylidene chloride-coated polyethylene terephthalate. However, in such a film, when a mechanical external force acts on the inorganic thin film of the surface layer by bending, rubbing, or the like, peeling or a defective portion occurs, so that the gas barrier property is significantly deteriorated.

Further, Japanese Patent Laid-Open No. 63-237940 discloses a composite film in which a heat-sealing layer such as an ethylene-propylene copolymer is formed on a film obtained by sputtering indium oxide or tin oxide by laminating or coating. It is disclosed. JP-A-4-
173137 and JP-A-1-202435 disclose a film in which a vapor deposition layer of silicon oxide and a protective layer are formed on the surface of a base film, and the protective layer is
It is composed of a laminate layer of a film such as an ethylene-vinyl alcohol copolymer or a coating layer of a thermosetting resin. However, the film in which the heat seal layer or the protective layer is formed on the inorganic oxide layer still has a low gas barrier property, and the oxygen permeability is only about 1 cc / m ² · 24 hr and the water vapor permeability is about 1 g / m ² · 24 hr. Further, the composite film obtained by laminating the resin film has a large film thickness.

As described above, a film having excellent gas barrier properties in addition to flexibility and transparency while suppressing deterioration of gas barrier properties due to the action of mechanical external force during processing and use, even if the coating layer is thin. Therefore, the protective effect of the contents and the visibility of the contents are still insufficient.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a gas barrier film having excellent gas barrier property and transparency even if the coating layer is thin.

Another object of the present invention is, in addition to the above characteristics,
An object of the present invention is to provide a gas barrier film which has a high gas barrier property even at high temperatures, is excellent in flexibility, and can suppress the deterioration of the gas barrier property even when a mechanical external force such as bending or rubbing acts.

[0009]

The present inventors have conducted extensive studies in order to achieve the above object, and as a result, when the inorganic layer formed on the surface of the base film layer was coated with a resin having a high gas barrier property, the transparency and flexibility of the resin were improved. It has been found that a film having excellent gas barrier properties is obtained even when the coating layer is thin, and the gas barrier properties are not deteriorated even under the action of mechanical external force or high temperature, and the present invention has been reached.

That is, according to the present invention, at least one surface of the base film layer (1) is covered with the barrier resin coating layer (3) through the transparent inorganic layer (2).
A gas barrier film coated with is provided.

In the present specification, the "barrier resin coating layer" has a thickness of 2 μm and a temperature of 25.
Oxygen gas permeability of 20 cc / m ² at 24 ° C for 24 hours or less, water vapor permeability of 20 g / m ² at 40 ° C and 90% relative humidity
-It means a layer containing a barrier resin for 24 hours or less.

As the polymer constituting the substrate film layer (1), various polymers capable of forming a film, for example, polyethylene, ethylene-ethyl acrylate copolymer, ionomer, polypropylene, ethylene-propylene copolymer, poly Polyolefin such as -4-methylpentene-1; polyethylene terephthalate, polyethylene-2,
Polyesters such as 6-naphthalate and polybutylene terephthalate; nylon 6, nylon 11, nylon 1
2, nylon 66, nylon 610, nylon 6/6
6, polyamide such as nylon 66/610; aromatic polyamide; polyvinyl chloride; polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride- (meth) acrylic acid ester copolymer Vinylidene chloride-based resins such as coalesced products; styrene-based resins such as polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer; polyvinyl alcohol; polyamideimide; polyimide; polyetherimide; polycarbonate; polysulfone; polyethersulfone Polyether ether ketone; Polyarylate; Polyphenylene sulfide; Polyphenylene oxide; Polyparaxylene; Polyacrylonitrile; Polytetrafluoroethylene, Polytri Rubber hydrochloride; cellulosic polymers such as cellophane; - Le Oro chloroethylene, tetrafluoroethylene fluorocarbon resins such as propylene copolymer and a copolymer comprising the components of the various polymers are exemplified.
These polymers may be used alone or in combination of two or more.

The light transmittance of the base film layer can be appropriately selected, but for the visibility and aesthetics of the package contents, the total light transmittance for white light rays is usually 40% or more, preferably It is desirable that it is 60% or more, and more preferably 80% or more.

The base film layer (1) is composed of an olefin polymer (especially polypropylene polymer), polyester (especially polyethylene terephthalate) and polyamide which are excellent in transparency, mechanical strength and packaging suitability. Is preferred.

The base film layer may be a single layer film or a laminated film in which two or more kinds of polymer layers are laminated. The thickness of the base film layer is not particularly limited and is appropriately selected in consideration of packaging suitability, mechanical strength, flexibility and the like. The thickness is usually 3 to 200 μm, preferably 5 to 100 μm.

The base film layer can be formed by a conventional film forming method, for example, a melt forming method such as an inflation method or a T die method, or a casting method using a solution. Further, the base film layer may be unstretched,
It may be uniaxially or biaxially stretched. As the stretching method, for example, a conventional stretching method such as roll stretching, rolling stretching, belt stretching, tenter stretching, tube stretching, or a combination of these can be applied. The draw ratio can be appropriately set according to the desired characteristics of the film, and is, for example, 1.5 to 20 times in at least one direction, preferably 2 to
It is about 15 times.

At least one surface of the base film layer is
It may be surface-treated. Examples of the surface treatment include corona discharge treatment, plasma treatment, glow discharge treatment, reverse sputtering treatment, flame treatment, chromic acid treatment, solvent treatment and surface roughening treatment. In addition, when the inorganic layer and the barrier resin coating layer are formed on the surface-treated surface of the base film layer, the adhesion can be improved.

An undercoat layer may be formed on the surface of the base film layer instead of or in addition to the surface treatment. The undercoat layer can be composed of various resins such as thermoplastic resins, thermosetting resins, light curable resins (electron beam curable resins, ultraviolet curable resins, etc.) and coupling agents. Specifically, for example, acrylic resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polycarbonate, cellulose-based polymer such as nitrocellulose and cellulose acetate, thermoplastic resin such as rosin-modified maleic acid resin; urethane-based resin , Urea resin, melamine resin, urea-melamine resin; thermosetting resin such as epoxy resin, alkyd resin, aminoalkyd resin; epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) Photocurable resins such as acrylates; silane coupling agents and the like. These may be used alone or in combination of two or more.

The undercoat layer may contain a colorant such as a general-purpose dye or pigment. The content of the colorant is appropriately selected within a range that does not impair the transparency of the film, and is usually about 1 to 30% by weight based on the resin forming the undercoat layer. The thickness of the undercoat layer is not particularly limited, but is usually about 0.1 to 5 μm.

The method of forming the undercoat layer is not particularly limited, and an organic or aqueous coating agent containing the components of the undercoat layer is used in a conventional coating method such as a roll coating method, a gravure coating method, a reverse coating method and a spray coating method. It is carried out by applying by a method and drying or curing. When a photocurable resin is used, it may be irradiated with an actinic ray.

The feature of the present invention is that the transparent inorganic layer (2) and the barrier resin coating layer (3) are combined to coat the surface of the substrate film (1) in a specific order. is there. By this composite structure, while suppressing the deterioration of the gas barrier property at the time of the action of mechanical external force or at high temperature,
In addition to high transparency and flexibility, a film having excellent gas barrier properties can be obtained even if the coating layer is thin.
This can be considered as follows.

That is, the film of the present invention comprises a transparent inorganic layer (2) and a barrier resin coating layer (3).
Since it has a high affinity with, no defect that causes a reduction in gas barrier property is generated. Also, not only is it highly transparent,
Even if the coating layer is extremely thin, a high gas barrier property can be obtained by the inorganic layer and the barrier resin coating layer, so that flexibility is not deteriorated and peeling or defects are not generated by an external force. Further, by combining the barrier resin coating layer and the inorganic layer, excellent gas barrier properties can be obtained even at high temperatures. Therefore, the film of the present invention, for example, during processing or use of the film, even when mechanical external force such as bending and rubbing acts, it is possible to suppress the deterioration of the gas barrier property, it can exhibit a high gas barrier property even at high temperatures. Excellent gas barrier properties can be maintained over a long period of time.

The inorganic material constituting the inorganic layer (2) is not particularly limited as long as it is an inorganic material capable of forming a transparent thin film. For example, beryllium, magnesium, calcium, strontium, barium and other elements of Group 2A of the Periodic Table; Titanium, zirconium, ruthenium, hafnium,
Periodic table transition elements such as tantalum; Periodic table 2B such as zinc
Group elements: Periodic table 3B group elements such as aluminum, gallium, indium, and thallium; Periodic table 4B group elements such as silicon, germanium, tin; Periodic table 6B group elements such as selenium and tellurium; Inorganic compounds such as oxides, halides, carbides, nitrides and the like can be mentioned. These can be used alone or in combination of two or more.

Preferred inorganic substances include, for example, elements of Group 2A of the periodic table such as magnesium, calcium, barium; elements of the periodic table such as titanium, zirconium, tantalum, ruthenium; elements of Group 2B of the periodic table such as zinc; aluminum, indium, etc. Periodic table group 3B elements such as thallium; periodic table group 4B elements such as silicon and tin; periodic table group 6B group elements such as selenium; and oxides containing these.

Of these, tin oxide, indium oxide, their composite oxides, and silicon oxides are preferable because of their excellent transparency and gas barrier properties. In particular, silicon oxide, in addition to the above characteristics, can form a dense thin film and has a high affinity with the polymer forming the barrier resin coating layer,
Even if a mechanical external force acts, no cracks or defects are generated in the inorganic layer, and excellent gas barrier properties can be maintained for a long period of time.
The silicon oxide includes not only silicon monoxide and silicon dioxide but also silicon oxide represented by the composition formula SiOx (wherein 0 <x≤2).

The thickness of the inorganic layer is usually 100 to 500.
0 Å (0.01-0.5 μm), preferably 300-1500 Å (0.03-
0.15 μm). 100 thickness
If it is less than angstrom, sufficient gas barrier property cannot be obtained, and if it exceeds 5,000 angstrom, the barrier property is not improved so much, which is economically disadvantageous.

The barrier resin coating layer is a resin having a high gas barrier property as described above, for example, vinylidene chloride copolymer, ethylene-vinyl alcohol copolymer,
Polyamide polymer, polyvinyl alcohol polymer,
It contains polyacrylonitrile polymer, urethane polymer and the like. The barrier resin of the gas barrier resin coating layer does not include resins that do not exhibit the above gas barrier properties, such as general urethane polymers. These barrier resins can be used alone or in combination of two or more.

Preferred barrier resins include, for example, vinylidene chloride copolymers and ethylene-vinyl alcohol copolymers. The vinylidene chloride-based copolymer is a copolymer of vinylidene chloride and another polymerizable monomer, and as such a polymerizable monomer, for example,
Various acrylates such as vinyl chloride, vinyl acetate, crotonic acid, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, acrylonitrile, methacrylonitrile Examples thereof include methacrylic acid and methacrylate corresponding to the above acrylates. Among these vinylidene chloride-based copolymers, vinylidene chloride-acrylonylolyl copolymer, vinylidene chloride-methacrylic acid copolymer, vinylidene chloride-acrylate copolymer, vinylidene chloride-methacrylate copolymer, vinylidene chloride-
Vinyl acetate copolymer and the like are preferable. The vinylidene chloride content in the vinylidene chloride-based copolymer is usually 85 to
It is about 99% by weight, preferably about 90 to 97% by weight.

The ethylene-vinyl alcohol copolymer is preferably a solvent-soluble ethylene-vinyl alcohol copolymer. In such an ethylene-vinyl alcohol copolymer, the ethylene content is usually 5 to 50 mol%, preferably 10 to 45 mol%, more preferably 2%.
It is about 5 to 35 mol%, and the molecular weight is usually 10,000 to 1
0,000, preferably about 40,000 to 50,000, saponification degree 99.5%
The above is desirable. Such a solvent-soluble ethylene-vinyl alcohol copolymer is soluble in water or a mixed solvent of water and alcohol and can form a thin film by coating.

The barrier resin coating layer is made of the above-mentioned barrier resin (preferably vinylidene chloride copolymer and ethylene-vinyl alcohol copolymer) depending on desired gas barrier properties (oxygen, water vapor, carbon dioxide, etc.). It may contain at least one resin and may contain a plurality of resins. Further, the barrier resin coating layer may be composed of a plurality of layers containing a barrier resin. For example, the barrier resin coating layer may be composed of a plurality of layers including a layer containing a vinylidene chloride copolymer and a layer containing an ethylene-vinyl alcohol copolymer. The content of the barrier resin in the barrier resin coating layer is 50% by weight or more, preferably 75 to 100% by weight, more preferably 90 to 100%.
It is about% by weight.

The thickness of the barrier resin coating layer is appropriately selected within a range that does not impair the characteristics of the film, but is usually 0.05 to 15 μm, preferably 0.1 to 10 μm.
m, more preferably about 0.25 to 5 μm. If the thickness is 0.05 μm or less, sufficient gas barrier properties cannot be obtained, and if it exceeds 15 μm, the gas barrier properties are not so improved, which is economically disadvantageous.

In the present invention, the thickness ratio of the inorganic layer (2) and the barrier resin coating layer (3) can be set appropriately, but the ratio affects the gas barrier property. Therefore, in order to obtain a high gas barrier property and resistance, the ratio of the thickness n2 (μm) of the barrier resin coating layer to the thickness n1 (μm) of the inorganic layer is n2 / n.
1 is usually 0.1 to 1500, preferably 0.5 to
It is desirable to be 60, more preferably about 2 to 50. If the thickness ratio is out of the above range, it becomes difficult to obtain sufficient gas barrier properties. Further, when the ratio is less than 0.1, defects are likely to occur in the inorganic layer due to external force,
Even if it exceeds 0, the gas barrier property is not improved so much and it is not economical.

On the surface of the barrier resin coating layer,
If necessary, a conventional surface treatment as exemplified in the base film layer may be applied.

The barrier resin coating layer is formed of another polymer such as ethylene-vinyl acetate copolymer,
Olefin-based polymers such as ethylene-ethyl acrylate copolymers; acrylic-based polymers; styrene-based polymers; polyesters; polyacetals; polyvinyl acetate;
Polyvinyl chloride; vinyl chloride-vinyl acetate copolymer; polyamide; urethane-based polymer; acrylonitrile-based polymer; polycarbonate; chlorinated polyolefin; cellulose-based polymer and the like may be contained.

The base film layer may contain various additives such as antioxidants, UV absorbers, heat stabilizers, and the like; cation-based and anion-based stabilizers, as long as transparency and gas barrier properties are not impaired. , Nonionic, antistatic agents such as amphoteric antistatic agents; crystal nucleus growth agents; styrene resins, terpene resins, petroleum resins, dicyclopentadiene resins, coumarone resins such as coumarone indene resins, phenol resins,
Hydrocarbon polymers such as rosin and its derivatives and hydrogenated resins thereof; plasticizers; fillers; higher fatty acid amides, higher fatty acids and their salts, higher fatty acid esters, natural waxes such as minerals and plants, polyethylene, etc. Waxes such as synthetic waxes; silica-based fine powders, alumina-based fine powders and other inorganic lubricants, polyethylene-based fine powders, acrylic-based fine powders and other organic lubricants, etc. Good.

In addition, the barrier resin coating layer may contain the above-mentioned additive, an anti-blocking agent, an adhesion improver such as polyethyleneimine and polyisocyanate.

The barrier film of the present invention is obtained by sequentially coating at least one surface of the base film layer (1) with the transparent inorganic layer (2) and the barrier resin coating layer (3). Obtainable.

The inorganic layer (2) is formed by a conventional method, for example,
Vacuum deposition method, reactive deposition method, sputtering method, reactive sputtering method, ion plating method, reactive ion plating method, CVD method, plasma CVD method,
The surface of the substrate film layer (1) can be formed by coating the surface with the inorganic substance by a laser CVD method or the like. The inorganic layer can be formed on one side or both sides of the base film layer.

The barrier resin coating layer can be formed by applying a coating liquid containing a barrier resin on the surface of the inorganic layer. The coating liquid can be prepared by selecting an appropriate solvent according to the kind of the barrier resin, and may be in the form of a solution or a dispersion liquid.

For example, the solvent of the solution coating solution containing the vinylidene chloride copolymer can be appropriately selected according to the kind of the vinylidene chloride copolymer, and examples thereof include ketones such as acetone, methyl ethyl ketone and cyclohexanone. Examples include ethers such as dioxane, diethyl ether and tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene and xylene; esters such as ethyl acetate and butyl acetate; amides such as dimethylformamide and mixed solvents thereof. . Further, the dispersion liquid is usually commercially available in the form of an O / W type emulsion.

The coating liquid containing the ethylene-vinyl alcohol copolymer can be usually prepared using a mixed solvent of water and alcohol. Examples of such alcohols include methanol, ethanol, propanol, isopropanol, cyclohexanol and the like.

The above-mentioned coating liquid may contain the above-mentioned various additives, and may further contain conventional additives such as defoaming agents and viscosity modifiers in order to enhance the coating property.

The coating method is not particularly limited, and a conventional method such as an air knife coating method, a roll coating method, a gravure coating method, a blade coater method, a dip coating method or a spraying method can be employed. After applying the coating liquid, the barrier resin coating layer can be formed by drying at a temperature of, for example, about 50 to 150 ° C.

The gas barrier film of the present invention contains
Various coating layers and laminate layers, for example, a slipping layer, an antistatic layer, a heat seal layer and the like may be formed depending on the type and application of the film.

The gas barrier film of the present invention is used for various packaging materials such as microwave oven foods, retort foods, frozen foods, microwave sterilization, flavor barriers, pharmaceuticals and precision electronic parts, and forming materials for balloons such as balloons. Can be suitably used as.

[0046]

The gas barrier film of the present invention is excellent in transparency because the surface of the substrate film layer is successively coated with an inorganic layer having transparency and a barrier resin coating layer having high gas barrier property. In addition, even if the coating layer is thin, it has a high gas barrier property. Further, even when a mechanical external force such as rubbing acts, or even at a high temperature, the deterioration of the gas barrier property can be suppressed, and the excellent gas barrier property can be exhibited for a long period of time.

[0047]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

Comparative Example 1 On one surface of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm, 5 × 10 5 was used as an evaporation source of SiO 2.
-Thickness 1000 by vacuum deposition under vacuum of ⁵ Torr
An angstrom silicon oxide vapor deposition layer was formed as an inorganic layer to obtain a composite film.

Examples 1 and 2 A vinylidene chloride copolymer (manufactured by Asahi Kasei Kogyo Co., Ltd., trade name: Saran resin F216) was mixed with toluene / tetrahydrofuran = 1/2 (weight ratio) in a resin concentration of 15
It was dissolved so as to have a weight percentage, and a coating liquid for a barrier resin coating layer was prepared.

This coating solution was applied to the vapor deposition surface of the silicon oxide vapor deposition film obtained in Comparative Example 1 using a bar coater to obtain a thickness of 0.5 μm (Example 1) and 2.5 μm.
After being applied as in (Example 2), it was dried in an oven at 105 ° C for 30 seconds to form a barrier resin coating layer to obtain a composite film.

Example 3 An ethylene-vinyl alcohol copolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Soarnol 30L) was dissolved in a mixed solvent of water / isopropanol = 1/1 (weight ratio),
The resin concentration was adjusted to 12% by weight to prepare a coating liquid for the barrier resin coating layer.

This coating solution was applied on the vapor deposition surface of the silicon oxide vapor deposition film obtained in Comparative Example 1 using a bar coater so that the thickness after drying was 4.0 μm, and
It was dried in an oven at 115 ° C. for 1 minute to form a barrier resin coating layer to obtain a composite film.

Comparative Examples 2 and 3 A thickness of 0.5 μm (Comparative Example 2) or 2.5 μm (Comparative Example 3) directly on a polyethylene terephthalate film.
A composite film was obtained in the same manner as in Examples 1 and 2 except that the barrier resin coating layer of 1 was formed.

Comparative Example 4 Instead of the coating liquid containing the vinylidene chloride copolymer, a general urethane resin solution [Takelac A615 manufactured by Takeda Yakuhin Kogyo Co., Ltd.] was used on the surface of the inorganic layer. A composite film was obtained in the same manner as in Example 1 except that a coating layer having a thickness of 5.0 μm was formed.

Comparative Example 5 Instead of the barrier resin coating layer, a urethane adhesive [TOYO Morton Co., Ltd., trade name ADCOTE 333E] was applied to the surface of the inorganic layer so that the thickness after drying was about 2 μm. Then, a 30 μm-thick unstretched ethylene-propylene copolymer film was laminated by a dry lamination method to obtain a composite film.

Comparative Example 6 Instead of the coating liquid containing the vinylidene chloride copolymer, a vinyl chloride-vinyl acetate copolymer solution [Denki Kagaku Kogyo Co., Ltd.] was used.
Manufactured by Denka 1000C, trade name, was used to obtain a composite film in the same manner as in Example 2 except that a coating layer having a thickness of 2.5 μm was formed on the surface of the inorganic layer.

Comparative Example 7 A coating layer having a thickness of 2.5 μm was formed on one surface of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm by using the same coating liquid for barrier coating as in Example 2. Then, on the surface of the coating layer,
A silicon oxide vapor deposition layer was formed in the same manner as in Comparative Example 1 to obtain a composite film.

Then, the oxygen gas permeability and water vapor permeability of the gas barrier films obtained in Examples and Comparative Examples were evaluated as follows.

Oxygen gas permeability: same pressure method (measuring instrument: Morcon
OXTRAN TWIN) was used under the conditions of 20 ° C. and 65% relative humidity. The unit is cc / m ² · 24 hr.

Water vapor transmission rate: Measuring instrument (PERMATRA, Morcon)
N W200) was used and the measurement was performed under the conditions of 40 ° C. and 90% relative humidity. The unit is g / m ² · 24 hr.

Further, the film was rubbed once by hand, the oxygen gas permeability and the water vapor permeability before and after the rubbing were measured, and the change in the gas barrier property due to the action of mechanical external force was evaluated.

The results are shown in the table. In the third embodiment,
The oxygen permeability before rubbing was below the measurement limit.

[0063]

[Table 1] As is apparent from the table, the films of Comparative Examples 1 to 7 do not have sufficient gas barrier properties, and the films of Comparative Examples 1, 6 and 7 show remarkable deterioration in gas barrier properties due to hand rubbing. On the other hand, the films of Examples 1 to 3 not only have extremely high gas barrier properties, but also can maintain excellent gas barrier properties even when mechanical external forces such as hand rubbing act. In particular, as is clear from comparison with Comparative Examples 1 to 3, by combining the inorganic layer and the barrier resin coating layer,
It exhibits extremely high gas barrier properties even when the thickness of the coating layer is small.

Claims (5)

[Claims] 1. A gas barrier film in which at least one surface of a base film layer (1) is covered with a barrier resin coating layer (3) through a transparent inorganic layer (2). 2. The barrier resin coating layer (3) comprises:
The gas barrier film according to claim 1, comprising a vinylidene chloride-based copolymer or an ethylene-vinyl alcohol copolymer. 3. The gas barrier film according to claim 1, wherein the transparent inorganic layer (2) is composed of silicon oxide. 4. The gas barrier film according to claim 1, wherein the barrier resin coating layer (3) has a thickness of 0.05 to 15 μm. 5. The thickness n of the transparent inorganic layer (2)
The gas barrier film according to claim 1, wherein the ratio n2 / n1 of the thickness n2 (μm) of the barrier resin coating layer to 1 (μm) is 0.1 to 1500.